Freiberg, Germany
Freiberg, Germany

Time filter

Source Type

Schiwy A.,RWTH Aachen | Maes H.M.,RWTH Aachen | Koske D.,RWTH Aachen | Flecken M.,RWTH Aachen | And 16 more authors.
Environmental Pollution | Year: 2016

The purpose of this study was to assess the ecotoxic potential of a new zero-valent iron nanomaterial produced for the elimination of chlorinated pollutants at contaminated sites. Abiotic dechlorination through the newly developed nanoscale zero-valent iron material and its effects on dechlorinating bacteria were investigated in anaerobic batch and column experiments. The aged, i.e. oxidized, iron material was characterization with dynamic light scattering, transmission electron microscopy and energy dispersive x-ray analysis, x-ray diffractometry and cell-free reactive oxygen measurements. Furthermore, it was evaluated in aerobic ecotoxicological test systems with algae, crustacean, and fish, and also applied in a mechanism specific test for mutagenicity. The anaerobic column experiments showed co-occurrence of abiotic and biological dechlorination of the common groundwater contaminant perchloroethene. No prolonged toxicity of the nanomaterial (measured for up to 300 days) towards the investigated dechlorinating microorganism was observed. The nanomaterial has a flake like appearance and an inhomogeneous size distribution. The toxicity to crustacean and fish was calculated and the obtained EC50 values were 163 mg/L and 458 mg/L, respectively. The nanomaterial showed no mutagenicity. It physically interacted with algae, which had implications for further testing and the evaluation of the results. Thus, the newly developed iron nanomaterial was slightly toxic in its reduced state but no prolonged toxicity was recorded. The aquatic tests revealed a low toxicity with EC50 values ≥ 163 mg/L. These concentrations are unlikely to be reached in the aquatic environment. Hence, this nanomaterial is probably of no environmental concern not prohibiting its application for groundwater remediation. © 2016


PubMed | Jülich Research Center, Water Technology Center, University of Stuttgart, UVR FIA GmbH and RWTH Aachen
Type: | Journal: Environmental pollution (Barking, Essex : 1987) | Year: 2016

The purpose of this study was to assess the ecotoxic potential of a new zero-valent iron nanomaterial produced for the elimination of chlorinated pollutants at contaminated sites. Abiotic dechlorination through the newly developed nanoscale zero-valent iron material and its effects on dechlorinating bacteria were investigated in anaerobic batch and column experiments. The aged, i.e. oxidized, iron material was characterization with dynamic light scattering, transmission electron microscopy and energy dispersive x-ray analysis, x-ray diffractometry and cell-free reactive oxygen measurements. Furthermore, it was evaluated in aerobic ecotoxicological test systems with algae, crustacean, and fish, and also applied in a mechanism specific test for mutagenicity. The anaerobic column experiments showed co-occurrence of abiotic and biological dechlorination of the common groundwater contaminant perchloroethene. No prolonged toxicity of the nanomaterial (measured for up to 300 days) towards the investigated dechlorinating microorganism was observed. The nanomaterial has a flake like appearance and an inhomogeneous size distribution. The toxicity to crustacean and fish was calculated and the obtained EC50 values were 163mg/L and 458mg/L, respectively. The nanomaterial showed no mutagenicity. It physically interacted with algae, which had implications for further testing and the evaluation of the results. Thus, the newly developed iron nanomaterial was slightly toxic in its reduced state but no prolonged toxicity was recorded. The aquatic tests revealed a low toxicity with EC50 values163mg/L. These concentrations are unlikely to be reached in the aquatic environment. Hence, this nanomaterial is probably of no environmental concern not prohibiting its application for groundwater remediation.


Kober R.,University of Kiel | Hollert H.,RWTH Aachen | Hornbruch G.,University of Kiel | Jekel M.,TU Berlin | And 15 more authors.
Environmental Earth Sciences | Year: 2014

Even today the remediation of organic contaminant source zones poses significant technical and economic challenges. Nanoscale zero-valent iron (NZVI) injections have proved to be a promising approach especially for source zone treatment. We present the development and the characterization of a new kind of NZVI with several advantages on the basis of laboratory experiments, model simulations and a field test. The developed NZVI particles are manufactured by milling, consist of 85 % Fe(0) and exhibit a flake-like shape with a thickness of <100 nm. The mass normalized perchloroethylene (PCE) dechlorination rate constant was 4.1 × 10−3 L/g h compared to 4.0 × 10−4 L/g h for a commercially available reference product. A transport distance of at least 190 cm in quartz sand with a grain size of 0.2–0.8 mm and Fe(0) concentrations between 6 and 160 g/kg (sand) were achieved without significant indications of clogging. The particles showed only a low acute toxicity and had no longterm inhibitory effects on dechlorinating microorganisms. During a field test 280 kg of the iron flakes was injected to a depth of 10–12 m into quaternary sand layers with hydraulic conductivities ranging between 10−4 and 10−5 m/s. Fe(0) concentrations of 1 g/kg (sand) or more [up to 100 g/kg (sand)] were achieved in 80 % of the targeted area. The iron flakes have so far remained reactive for more than 1 year and caused a PCE concentration decrease from 20.000–30.000 to 100–200 µg/L. Integration of particle transport processes into the OpenGeoSys model code proved suitable for site-specific 3D prediction and optimization of iron flake injections. © 2014, Springer-Verlag Berlin Heidelberg.


Georgi-Maschler T.,RWTH Aachen | Friedrich B.,RWTH Aachen | Weyhe R.,Accurec Recycling GmbH | Heegn H.,UVR FIA GmbH | Rutz M.,UVR FIA GmbH
Journal of Power Sources | Year: 2012

In cooperation with the industrial project partners ACCUREC Recycling and UVR-FIA a recycling process specially dedicated to portable Li-ion batteries was developed combining a mechanical pretreatment with hydro- and pyrometallurgical process steps. Therefore not only the recovery of cobalt but also the recovery of all other battery components, especially of lithium was of interest. Besides the characterization and evaluation of all generated metallic material fractions, the focus of the research work was the development of a pyrometallurgical process step in an electric arc furnace for the carbo-reductive melting of the fine fraction extracted from spent Li-ion batteries. This fine fraction mainly consists of the cobalt and lithium containing electrode material. Since a selective pyrometallurgical treatment of the fine fraction for producing a cobalt alloy has not been done before, the proof of feasibility was the main aim. © 2012 Elsevier B.V. All rights reserved.


Clemens P.,Mahltechnik und Automation | Espig D.,Technologieberatung | Pohl M.,Dyckerhoff AG | Sievert T.,Dyckerhoff AG | Schnedelbach G.,UVR FIA GmbH
Cement International | Year: 2014

Although the tube ball mill was invented 120 years ago its grinding media charge grading is still calculated on subjective guidelines. The technical literature only provides inadequate solutions to more recent requirements, such as the design of the fine grinding chamber of a ball mill for finish grinding cement that has already been preground in a high-pressure roller mill. Assisted by trials and based on systematically acquired knowledge this article not only provides new findings but also suggests how the fine grinding chambers in ball mills should be designed and the grinding media charge should be graded. Starting from the fact that for two ball mills of different size virtually the same specific power consumption is required if the same comminution progress is to be achieved in the two mills the opportunity is taken to transfer the results from a batch-operated pilot plant mill to an industrial ball mill. The article focuses on results obtained by measurements on an industrial ball mill at Dyckerhoff AG's Geseke cement plant. This is used as the second, open-circuit, grinding stage to an upstream KHD roller press operated in circuit with a separator. It grinds cement that has been preground to 4600 cm2/g Blaine to an end fineness of 5300 cm2/g Blaine. When the grinding balls in the second grinding chamber with diameters of 12 to 30 mm had been replaced by virtually the same weight of grinding balls with dimensions of 12 to 16 mm the power consumption of the mill motor fell by 18.9 % from 370 kW to 300 kW and the output rose by 11.7 % from 47.0 t/h to 52.5 t/h. The cement produced after this change in grinding media fulfilled all the quality requirements of a high-grade cement. The results obtained in the operational trials are regarded as an incentive to carry out further investigations into the influence of ball size and charge grading on output, particle size distribution and power consumption in the fine grinding chambers of ball mills and at the same time to consider how these parameters can be taken better into account when designing and calculating the performance of a ball mill.


Schmidt K.,UVR FIA GmbH | Kamptner A.,UVR FIA GmbH | Schnedelbach G.,UVR FIA GmbH | Polster M.,UVR FIA GmbH | Ebertz B.,CeramTec GmbH
Aufbereitungs-Technik/Mineral Processing | Year: 2010

For grinding high-grade speciality products with strict specifications for particle size distribution, purity and reactivity, tumbling mills with non-classifying linings and grinding media made of special ceramic are used. To improve grinding efficiency, a ceramic classifying lining was to be developed and tested. In semiindustrial grinding tests with silica sand and limestone, it could be proven that energy savings or increases in throughput rates between 5-25 % can be achieved with the new lining.


The efficient and economical use of thermal energy is associated with the utilization of solar power. Test latent-heat storages in different sizes were filled with latent heat storage material LC-58. Macroencapsulation was used for sealing the corrosive LC-58 against water. A new and innovative system for the storage of solar thermal energy is described. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.


Kamradt A.,Martin Luther University of Halle Wittenberg | Borg G.,Martin Luther University of Halle Wittenberg | Schaefer J.,UVR FIA GmbH | Kruse S.,RWTH Aachen | And 12 more authors.
Chemie-Ingenieur-Technik | Year: 2012

Dumps in the Central German Mansfeld mining district have been investigated by a multi-disciplinary research team to develop a holistic concept for the recovery of base and trace metals from low-grade Kupferschiefer ore. Geochemical and mineralogical data from representative sampling indicate that the low-grade Kupferschiefer dumps contain significant amounts of Cu (0.6 %) and Ag (up to 800 ppm), besides exploitable grades of Pb and Zn. Additionally to flotation and hydrometallurgy, first shake flask bioleaching experiments on otherwise untreated Kupferschiefer ore yield Cu recovery rates of up to 95 %. A total of 900 t Cu and 5 t Ag contained in black copper can thus be produced from the pilot dump of 100 000 m 3 low-grade Kupferschiefer ore. Additionally, large volumes of limestone waste, separated from the dumps by sensor-based sorting, can be utilized as aggregate in the construction industry. Mine dumps of the former Mansfeld mining district, Central Germany, contain significant metal resources. A holistic concept has been developed for the recovery of base and trace metals from the low-grade Kupferschiefer-bearing dumps. The study combines resource-efficient use in mineral processing and sustainable utilization of waste. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Loading UVR FIA GmbH collaborators
Loading UVR FIA GmbH collaborators